Proteins are broken down into amino acids. Side note: the enzyme that helps in breaking protein down is called the protease
<span>D. Lancelet, are examples of an invertebrate chordate:)</span>
Yes all organisms display cellular respiration.
Natural selection means that the organisms better adapted to their environment, that is, they have developed the right characteristics/skills/response to the external ambient, have higher chance to survive, making the next generations genetically inherit such acquired surviving characteristics.
These generations will thus have a higher chance of survival, making these species being "naturally selected" as survivors, while those who haven't or are slower in this process, have a higher risk of elimination.
